Power Brake Actuation Land Rover Range Rover L322

SPECIFICATIONS

GENERAL SPECIFICATIONS

TORQUE SPECIFICATIONS

COMPONENT LOCATION - 4.2L SUPERCHARGED

Note. left-hand drive (LHD) installation shown, right-hand drive (RHD) installation similar

Scheme 34

COMPONENT LOCATION - 4.4L NATURALLY ASPIRATED

Note. RHD installation shown, LHD installation similar

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OVERVIEW

Power assistance for the brakes is provided by a vacuum operated brake booster. On 4.2L and 4.4L gasoline vehicles, the vacuum is produced by the intake manifold and an electric vacuum pump. On TdV8 vehicles the vacuum is produced by an engine driven vacuum pump.

VACUUM PIPES

Plastic vacuum pipes connect the brake booster to the vacuum source. Check valves are incorporated into the vacuum pipes.

On gasoline vehicles there are 2 check valves, to maintain the vacuum in the brake booster when the throttle is open and the vacuum pump is not running. The check valves also prevent fuel vapor entering the brake booster.

On TdV8 vehicles there is a single check valve integrated into the vacuum pipe connection with the brake booster. The check valve maintains a vacuum in the brake booster when the engine is running at low speeds, and the vacuum pump is operating at less than the optimum.

BRAKE BOOSTER

The brake booster provides power assistance to increase the braking effort applied by the driver. The assembly is attached to the front of the pedal box and comprises a circular housing containing a diaphragm, push rods, valve and filter. A push rod at the rear of the housing protrudes through an aperture in the bulkhead and is connected to the brake pedal.

The vacuum pipe is connected to a port in the front face of the brake booster housing.

With the brake pedal released and the engine running, a vacuum is present on both sides of the diaphragm. When the brake pedal is pressed, the rear push rod moves forward and opens the valve to allow atmospheric pressure through the filter into the pedal side of the diaphragm. The pressure differential acting on both sides of the diaphragm increases the pressure being applied by the brake pedal.

In the event that the brake booster fails, the hydraulic system will still function but will require greater pedal effort due to the lack of vacuum assistance.

VACUUM PUMP - 4.2L SUPERCHARGED AND 4.4L NATURALLY ASPIRATED

On gasoline vehicles the electric vacuum pump supplements the main vacuum supply from the engine manifold.

The vacuum pump is installed in the engine compartment, on a mounting bracket attached to the side of the right-hand (RH) suspension tower. Two anti-vibration mounts on the vacuum pump are located on studs on the mounting bracket and secured with nuts.

The vacuum pump consists of a radial vane pump driven by an electric motor. The rotor and vanes of the pump are made from a self-lubricating carbon based material. A stub pipe is installed in the inlet of the pump to provide a connection point for the vacuum pipe from the brake booster. A second stub pipe, which is covered by a rubber shroud, is installed in the outlet from the pump.

Operation of the vacuum pump is controlled by the engine control module (ECM), which uses the vacuum pump relay in the battery junction box (BJB) to switch power to the vacuum pump. The ECM controls the time for which the vacuum pump is energized and also features built-in safeguards to protect the pump from overuse.

Scheme 37

The Vacuum required for brake booster operation on TdV8 vehicles is provided by an engine driven vacuum pump. The vacuum pump is a radial vane type pump mounted to the front of the RH cylinder head which is driven by the intake camshaft. The vacuum pipe from the brake booster connects to an elbow on the rim of the vacuum pump.

The vacuum pump is lubricated and cooled by engine oil supplied to a port in the front face of the vacuum pump from a gallery in the cylinder head. The oil return is through a vent in the front face of the pump into a drain cavity in the cylinder head. Air extracted from the brake booster is vented into the drain cavity with the returning engine oil.

The vacuum pump is also used to supply vacuum for operation of the following components

1. The exhaust gas recirculation (EGR) system. For additional information, refer to: Electronic Engine Controls (303-14C, Description and Operation).
2. The adaptive engine mounts. For additional information, refer to: Electronic Engine Controls (303-14C, Description and Operation).

CONTROL DIAGRAM - 4.2L SUPERCHARGED AND 4.4L NATURALLY ASPIRATED

Note. A = Hardwired connection

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1. Disconnect the battery ground cable. Refer to «Specifications»(/land-rover/range-rover/l322-2005-2009/remont/charging-system/#charging-system-general-information__specifications) .
2. Remove the plenum chamber. Refer to «Plenum Chamber»(/land-rover/range-rover/l322-2005-2009/remont/automatic-hvac-system/#air-distribution-and-filtering) .
3. Remove the auxiliary battery compartment side wall. Disconnect the hood switch electrical connector. Remove the wiper motor support bracket bolt. Remove the 3 bolts. Remove the 2 nuts.
4. Remove the brake master cylinder. Refer to «Brake Master Cylinder - Vehicles With: Standard Brakes»(/land-rover/range-rover/l322-2005-2009/remont/brakes-control-systems/#hydraulic-brake-actuation) .
5. Disconnect the brake booster vacuum hose from the brake booster.
6. Remove the floor console extension. Remove the screw. Release the 2 clips.
7. Remove the drivers side closing trim panel. Remove the 3 screws. Disconnect the footwell lamp electrical connector. Release the vehicle diagnostic socket.
8. Release the brake booster. Remove and discard the 2 nuts. Release the brake booster push rod from the brake pedal.
9. Remove the brake booster. Remove and discard the gasket.

INSTALLATION

1. Install the brake booster. Tighten the nuts to 26 Nm (19 lb.ft). Secure the brake booster push rod to the brake pedal.
2. Install the driver side closing trim panel. Connect the footwell lamp electrical connector. Secure the vehicle diagnostic socket. Tighten the screws.
3. Install the floor console extension. Secure the clips. Tighten the screw.
4. Connect the brake booster vacuum hose to the brake booster.
5. Install the brake master cylinder. Refer to «Brake Master Cylinder - Vehicles With: Standard Brakes»(/land-rover/range-rover/l322-2005-2009/remont/brakes-control-systems/#hydraulic-brake-actuation) .
6. Install the auxiliary battery compartment side wall. Install the 2 nuts. Install the 3 bolts. Install the wiper motor support bracket bolt. Connect the hood switch electrical connector.
7. Install the plenum chamber. Refer to «Plenum Chamber»(/land-rover/range-rover/l322-2005-2009/remont/automatic-hvac-system/#air-distribution-and-filtering) .
8. Connect the battery ground cable. Refer to «Specifications»(/land-rover/range-rover/l322-2005-2009/remont/charging-system/#charging-system-general-information__specifications) .

REMOVAL

1. Disconnect the battery ground cable. Refer to «Specifications»(/land-rover/range-rover/l322-2005-2009/remont/charging-system/#charging-system-general-information__specifications) .
2. Remove the plenum chamber. Refer to «Plenum Chamber»(/land-rover/range-rover/l322-2005-2009/remont/automatic-hvac-system/#air-distribution-and-filtering) .
3. Remove the auxiliary battery compartment side wall. Disconnect the hood switch electrical connector. Remove the wiper motor support bracket bolt. Remove the 3 bolts. Remove the 2 nuts.
4. Remove the brake master cylinder. Refer to «Brake Master Cylinder - Vehicles With: High Performance Brakes»(/land-rover/range-rover/l322-2005-2009/remont/brakes-control-systems/#hydraulic-brake-actuation) .
5. Disconnect the brake booster vacuum hose from the brake booster.
6. Remove the floor console extension. Remove the screw. Release the 2 clips.
7. Remove the drivers side closing trim panel. Remove the 3 screws. Disconnect the footwell lamp electrical connector. Release the vehicle diagnostic socket.
8. Release the brake booster. Remove and discard the 2 nuts. Release the brake booster push rod from the brake pedal.
9. Remove the brake booster. Remove and discard the gasket.

1. Install the brake booster. Tighten the nuts to 26 Nm (19 lb.ft). Secure the brake booster push rod to the brake pedal.
2. Install the driver side closing trim panel. Connect the footwell lamp electrical connector. Secure the vehicle diagnostic socket. Tighten the screws.
3. Install the floor console extension. Secure the clips. Tighten the screw.
4. Connect the brake booster vacuum hose to the brake booster.
5. Install the brake master cylinder. Refer to «Brake Master Cylinder - Vehicles With: High Performance Brakes»(/land-rover/range-rover/l322-2005-2009/remont/brakes-control-systems/#hydraulic-brake-actuation) .
6. Install the auxiliary battery compartment side wall. Install the 2 nuts. Install the 3 bolts. Install the wiper motor support bracket bolt. Connect the hood switch electrical connector.
7. Install the plenum chamber. Refer to «Plenum Chamber»(/land-rover/range-rover/l322-2005-2009/remont/automatic-hvac-system/#air-distribution-and-filtering) .
8. Connect the battery ground cable. Refer to «Specifications»(/land-rover/range-rover/l322-2005-2009/remont/charging-system/#charging-system-general-information__specifications) .

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1. Disconnect the battery ground cable. Refer to «Specifications»(/land-rover/range-rover/l322-2005-2009/remont/charging-system/#charging-system-general-information) .
2. Remove the brake vacuum pump. Release and disconnect the electrical connector. Disconnect the vacuum line. Remove the 2 nuts.
3. Remove the 2 rubber insulators. Remove the metal inserts.

1. To install, reverse the removal procedure. Tighten the nuts to 5 Nm (4 lb.ft).

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1. Disconnect the battery ground cable. Refer to «Specifications»(/land-rover/range-rover/l322-2005-2009/remont/charging-system/#charging-system-general-information__specifications) .
2. Raise and support the vehicle.
3. Remove the cooling fan.
4. Release the coolant expansion tank. Remove the 2 bolts.
5. Release the charge air cooler RH outlet hose. Release the clip.
6. Release the wiring harness. Remove the nut. Release the wiring harness fir tree clip
7. Disconnect the brake booster vacuum line from the brake vacuum pump.
8. Disconnect the engine oil pick-up hose. Release the clip.
9. Remove the brake vacuum pump. Remove the nut. Remove the stud. Remove the 2 bolts. Remove and discard the gasket.

1. Install the brake vacuum pump. Install a new gasket. Tighten the stud to 10 Nm (7 lb.ft). Tighten the nut to 23 Nm (17 lb.ft). Tighten the bolts to 23 Nm (17 lb.ft).
2. Connect the oil pick-up hose. Secure with the clip.
3. Connect the brake booster vacuum line to the brake vacuum pump.
4. Secure the wiring harness. Secure the fir tree clip. Tighten the nut to 10 Nm (7 lb.ft).
5. Install the charge air cooler RH outlet hose. Secure with the clip.
6. Secure the coolant expansion tank Tighten the bolts to 10 Nm (7 lb.ft).
7. Install the cooling fan.
8. Connect the battery ground cable. Refer to «Specifications»(/land-rover/range-rover/l322-2005-2009/remont/charging-system/#charging-system-general-information__specifications) .

See also:
• Specifications
• Plenum Chamber
• Brake Master Cylinder - Vehicles With: Standard Brakes
• Specifications